The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Ambulance officer Michael Freeman says this will have a devastating effect on workers and the community.

"If important fatigue-management and rostering provisions are removed from agreements we feel it will only be a matter of time before this will lead to injury or even the death of an officer, patient or member of the public," he said.

Union members protested outside parliament on Friday with an urn to symbolise the death of workers' rights and the threat it could have on ambulance officers' lives.

This coincides with the Legal Affairs and Community Safety Committee's public meeting about the impact of the proposed amendments.